Abstract Abrasive Water Jet Research Articles

Pocket Milling of AISI 1045 Steel using Abrasive Water Jet Machining by Varying Contours

Abrasive water jet machining (AWJM) is an innovative machining technology recognized for cutting tougher materials smoothly. This study investigates the significance of AWJM parameters on surface roughness (SR) and material removal rate (MRR); while machining AISI1045medium carbon steel. Pocket milling has been done on the material; pockets of definite size/specifications are machined and associated MRR and SR are investigated. The Input parameters considered are Standoff distance (SOD), Cutting feed, Pressure. Experimental parameters are analyzed as per Taguchi method (DOE). The interaction effects of input process parameters are studied through 3D contour plots. ANOVA is used to determine the influencing parameter, and it has been verified that the ideal combination of Taguchi process parameters satisfies the actual machining of material.

Life Cycle Environmental and Economic Comparison of Water Droplet Machining and Traditional Abrasive Waterjet Cutting

Abrasive waterjet (AWJ) cutting is a manufacturing technique, which uses a high-speed waterjet as the transport medium for abrasive particles to erode and cut through metal workpieces. The use of abrasives has significant environmental impacts and leads to the high operating costs of AWJ cutting. Therefore, it is important to investigate whether other metal cutting approaches can perform the same tasks with reduced environmental and economic impacts. One such manufacturing innovation is water droplet machining (WDM). In this process, the waterjet, which is immersed in a sub-atmospheric pressure environment, is discretized into a train of high velocity water droplets, which are able to erode and cut through the metal workpiece without abrasives. However, the cutting velocity of WDM is two orders of magnitude slower than AWJ. In this paper, a comparative life cycle and life cycle cost assessments were performed to determine which waterjet cutting technology is more beneficial to the environment and cost-efficient, considering their impacts from cradle to grave. The results show lower environmental and economic impacts for AWJ compared to WDM due to the AWJ’s ability to cut more metal over the service life than the WDM. Further sensitivity analyses give insight into how the change in abrasive rate is the most sensitive input for the AWJ, whereas the machine lifetime and electricity usage are the most sensitive inputs for the WDM. These results provide a valuable comparison between these alternative waterjet cutting technologies.

Influence of Abrasive Water Jet (AWJ) on Surface Roughness

Abrasive water jet (AWJ) is one of the most advanced and valuable non-traditional machining processes because of its massive advantages of removing metals ranging from hard to soft. This paper focused on studying the influence of jet pressure, feed rate and standoff distance on surface roughness during cutting carbon steel using abrasive water jet cutting. A surface roughness device assessed the surface roughness by performing sixteen experiments to identify the distinct texture of the surface. Based on the experiences, the best surface roughness value was 3.14 μm at jet pressure 300 MPa, standoff distance 4mm and feed rate 30 mm/min. The Taguchi method was introduced to implement the experiments and indicate the most influential process parameters on average surface roughness. The experimental results reveal that feed rate has a significant effect on average surface roughness.

Visualization and evaluation of the spatial kinematic rotation error of a five-axis abrasive water jet cutting head

Abrasive water jet (AWJ) technology has been more and more used in space curved surface machining. Dynamic angle compensation technology based on the five-axis linkage control system was the core to eradicate the errors caused by taper and jet lag in AWJ machining and enabled this technology to get into some precision fields. But the spatial kinematic rotation error of the cutting head in five-axis AWJ machine tool which has a direct impact on AWJ machining performance and accuracy has not been systematically studied. Aimed at this, this paper explored a new method based on spatial meshes to obtain the spatial kinematic rotation error of the cutting head. According to the visualization of the experimental data, the spatial kinematic rotation error was found with no obvious pattern. Then, a dimension reduction method was employed to mining these data and enabled this irregular error to be predicted with mapping method. According to the verification experiments, this new method was proved efficiently and useful in predicting the spatial kinematic rotation error.

Failure Mechanism and Effect of Nozzle Parameters on Abrasive Water Jet Rock Breaking

Abrasive Water Jet (AWJ) technology has vast application prospects in the assisted drill-blasting of tunnel excavation, with the advantages of fast-breaking speed, low tool wear, less dust, and good mobility. Nevertheless, AWJ technology has some limitations and shortcomings, such as the small effective fracturing range and parameter mismatch, which influence the fracturing effect of AWJ. To solve the abovementioned issues, it is necessary to study the failure mechanism of rock impacted by AWJ and nozzle parameter effects on rock fragmentation. Based on the coupling algorithm of Smooth Particle Hydrodynamics and Finite Element Method (SPH-FEM), in this research, the numerical model of AWJ impacting rock was established, and the result was verified with Computed Tomography (CT) scanning after the AWJ impacting rock experiment and image processing technology. Through the analysis of the stress characteristics of typical particles in the rock model at different stages and positions, the formation and expansion mechanisms of the crater and the cracks were revealed. Additionally, in this research, the comprehensive damage factor of rock (X) representing the fragmentation degree was defined. By comparatively analyzing X-values with certain technical parameters of AWJ, the importance ranking of the nozzle parameters, the effect of each nozzle parameter on the rock fragmentation, and the optimal parameter combination were also investigated.

Titanium Alloy Milling Using Abrasive Water Jet for Repair Application: Modifications in Surface Quality and Material Integrity Following Plain Water Jet Cleaning

Abrasive Water Jet (AWJ) machining has proven to be an effective and versatile technique for milling various kinds of materials, even with low machinability such as aerospace grade titanium alloy Ti6Al4V. Many studies have been performed in order to master this technology and produce geometrically accurate shapes. However, in the context of bonding repairs which require surfaces free from foreign bodies, AWJ machining presents a significant drawback in form of abrasive grit embedment. The goal of this present work is then to investigate the effect of a post-AWJ machining cleaning operation using Plain Water Jet process (PWJ – i.e. without abrasive particles) on the surface quality and material properties. For this, several characterization techniques were employed. It was concluded that the contamination has been reduced by 65% without noticeable changes in depth of cut and crater volume. The AWJ milling operation produced surface and subsurface hardening as well as biaxial compressive residual stress, mostly piloted by the jet pressure. PWJ cleaning reduced the depth of hardening without clear modification in surface hardness.

Machinability and Delamination Studies on Glass Fiber Reinforced Polymer Matrix Composite Cut by Abrasive Water Jet Machine

Abrasive water jet machining possesses inherent technological and manufacturing advantages unmatched by most machine tools. They are generally used in automotive, marine and aerospace industries for machining of composites. However, abrasive water jet cutting of GFRP laminates possesses several challenges, such as surface finish and delamination of the cutspecimen. Henceforth, more experimental work is needed to provide sufficient machinability databases for manufacturing industries. This paper presents an experimental study for cutting GFRP laminates. Different AWJM conditions including pressure, traverse speed and abrasive flow rate are analyzed using full factorial design of experiments. Machining process responses such as surface roughness (Ra), top and bottom kerf width, kerf taper, delamination of fibers have been evaluated using analysis of variance (ANOVA) technique. The optimum process parameters for AWJM of glass fiber reinforced polymers have beensuggested.

CFD analysis and field observation of tool erosion caused by abrasive waterjet fracturing

Abrasive waterjet (AWJ) fracturing has become an accepted horizontal multistage stimulation technique due to its flexibility and high efficiency of extensive fracture placement. The downhole tool failure of AWJ fracturing becomes an issue in the massive hydraulic fracturing because of high velocity and proppant erosion. This paper proposed a 3D computational fluid dynamics (CFD)-based erosion model by considering high-velocity waterjet impact, proppant shear erosion, and specific inner structure of hydra-jet tool body. The discrete phase approach was used to track the proppant transport and its concentration distribution. Field observation provides strong evidence of erosion patterns and mechanisms obtained from CFD simulation. The results show that the erosion rate has a space dependence in the inner wall of the tool body. The severe erosion areas are primarily located at the entries of the nozzle. Evident erosion patterns are found including a ‘Rabbit’s ear’ erosion at the upper-layer nozzles and a half bottom loop erosion at the lower-layer nozzles. Erosion mechanisms attribute to high flow velocity at the entry of nozzles and the inertia force of proppant. Sensitivity analysis demonstrates that the pumping rate is a primary factor contributing to erosion intensity.

Depth of cut prediction in abrasive waterjet turning using a new finite element model

Abrasive waterjet turning (AWJT) is an advanced machining process that could be used for turning cylindrical workpieces with the advantages of low vertical forces and negligible thermal distortion. Radial-mode AWJT is characterised by better utilisation of jet energy and high material removal rate. However, the prediction of depth of cut (DOC) is difficult due to the interaction of several process parameters. In this paper, a new finite element (FE) model was developed to predict the DOC in radial-mode AWJT. The workpiece material is AISI 4340 alloy steel and it is modelled with Johnson-Cook (JC) constitutive model. Two AWJT parameters: waterjet pressure and abrasive flow rate, were considered in the FE model with three levels for each parameter. A full factorial design was selected to evaluate the combined effect of these independent parameters. The resulting crater profile was utilised to estimate the DOC at each parameter combination. In order to evaluate the model accuracy, the DOC results were compared with published experimental data from the literature at the same AWJT conditions. The comparison showed a good agreement between the FE results and the published experimental results.

NEW CHALLENGES IN ABRASIVE WATER JET MACHINING

Abrasive water jet machining (AWJM) is one of the most important method used in cutting different types of materials: alloy sheet, marble, glass, rocks. This process is used in the aeronautic, automotive, metallurgy industries and even in some art techniques and textile industry. The method consists in transforming the kinetic energy of a solid particle directed with water jet at a high pressure to remove material through erosion and abrasion. AWJM is low cost equipment compared to other conventional cutting technologies. This paper is an attempt to review the achievements made in AWJM technology for different hardness materials.

Technical-economic evaluation of abrasive recycling in the suspension fine jet process chain

Abrasive waterjet generation methods such as the conventional injection jet method and the suspension jet method have a strong influence on properties and costs of the machined products, particularly ones made of difficult-to-machine materials, e.g., ceramics. Since recycling may reduce the needed amount of materials significantly, the same holds true for recycling processes and technologies within the process chains of abrasive waterjet methods. In this paper, a methodology for integrated technical-economic evaluation of processes is presented and applied to the process technology of abrasive recycling in the suspension fine jet process chain aiming to show the technology’s technical as well as economic potential. Research and development regarding such processes and technologies may contribute to gain competitive advantages for companies as they can differentiate from competitors by offering or processing materials with distinctive properties and/or lower prices causing customer’s benefit. Consequently, it is also of great importance for companies applying waterjet cutting methods to know whether and which recycling technologies are promising from both a technical and an economic point of view. Experiments show that a significant share of the input material (abrasive particles) can be reused after recycling. The monetary appraisal reveals that technical potential results in considerably lower costs compared to the suspension jet method without recycling.

Mathematical modelling on multiple variables in machining LaPO<SUB align="right">4/Y<SUB align="right">2O<SUB align="right">3 composite by abrasive waterjet

Abrasive water jet machine (AWJM) cutting technology is used to process many engineering materials which have low toughness and poor thermal conductive property. In this study, LaPO4/Y2O3 ceramic composite, that possesses no phase transformation at high operating temperature and good thermal barrier material, is used. AWJM with garnet of 80 mesh size as abrasive is characterised with various process parameters. Here, material removal rate (MRR), kerf angle (KA) and surface finish (Ra) are investigated by using the three influencing parameters such as jet pressure (JP), stand-off distance (SOD) and traverse speed (TS). L27 orthogonal array is used to record the experimental observations. The empirical model is developed by multilinear regression analysis (MRA) for MRR, KA and Ra. Analysis of variance (ANOVA) and response tables show the influences and the contribution of each independent variable over the dependent response.

An Investigation in Abrasive Waterjet Cutting of Al6061/SiC/Al2O3 Composite Using Principal Component Based Response Surface Methodology

Abrasive waterjet was found effective in cutting materials like glass, steel and aluminium for various industrial applications. The effect of process parameters on abrasive waterjet cutting (AWJC) of Al6061/SiC/Al2O3 composite was disclosed in the present work. The cutting parameters taken for study were traverse speed, abrasive flow rate, water pressure and stand-off distance. Surface roughness, kerf width and bevel angle of cut were observed as the quality characteristics for various cutting trials. Experiments were designed using Taguchi's L18 orthogonal array and an integrated technique of principal component based response surface methodology (PC-RSM) was disclosed for designing the parameters. Significant improvements were observed in the quality characteristics obtained with optimal parameter setting identified by PC-RSM approach. Abrasive waterjet parameters like water pressure, stand-off distance and the interaction between abrasive flow rate and traverse speed were found to be influential on the quality characteristics.

A New Look into the Loose Particle Impact Process for Ductile Materials

Abrasive waterjet machining involves the impact of micro-particles at high or ultrahigh velocities. The material removal mechanism for ductile materials has been popularly accepted for over a half century as cutting wear and deformation wear caused by the component of impact force parallel and perpendicular to the target surface respectively. However, this definition of erosion mechanisms does not give an insight into the erosion process, but describes a surface phenomenon of the event. A computational study has been undertaken to reveal the underlying mechanisms of the material removal process. Based on the findings, the impact erosion mechanisms are re-defined as material destruction through (a) failures induced by inertia, (b) failure induced by elongation, and (c) failure induced by adiabatic shear bending. This new definition appears to better represent the physical process of material deformation and removal by loose micro-particle impacts at high and ultrahigh velocities.

EXPERIMENTAL ANALYSIS OF THE INFLUENCE OF FEED RATE ON QUALITY OF CUTS PERFORMED BY AWJ

Abrasive waterjet (AWJ) cutting technology is one of the most recent developed non-traditional processes used in industry for the processing of difficult-to-cut materials which usually lead to a pronounced wear of conventional tools and generation of damaged surfaces. The efficiency and the quality of AWJ depend on many parameters, some of them precisely controllable (e.g. water jet pressure, feed rate) while others uncontrollable (e.g. focusing tube size, waterjet orifice size). The aim of current study was to analyze the influence of feed rate at low working pressures on the quality of cuts, quantified by the parameters specified in the ISO/WD/TC44 N 1770 standard.

An Experimental Study of Influence of Process Parameters on Kerf Properties of Abrasive Water Jet Machined Carbon Fibre Reinforced Polymer

Abrasive water jet machining is an emerging technology for composite material processing. The machining of carbon fibre reinforced polymer by conventional means is difficult due to excessive tool wear, delamination and improper kerf properties. This paper presents experimental study of influence of process parameters on kerf top width of abrasive water jet machined carbon fibre reinforced polymer. The process parameters namely water pressure, stand-off distance, traverse rate, and abrasive mass flow rate are considered in the present work. Taguchi's design of experiment and analysis of variance are used to investigate the effect of process parameters on kerf top width. It is observed that stand-off distance and traverse rate are most significant parameters in influencing the kerf top width. A set of optimum process parameters is identified on the basis of analysis of the experimental data. A regression model is developed using multi-linear regression approach on the basis of experimental analysis. Results of the present work are successfully compared with the published literature.

Study on the characteristics of pressure variation in ASJ system

Abrasive water jet (AWJ) technology have been widely used for machining, while most commercial applications are based on the injection abrasive water jet (injection AWJ) technology. Compared with injection AWJ, abrasive suspension jet (ASJ) has higher energy efficiency. Under the same system pressure, the material removal rate by ASJ is up to five times higher than that by injection AWJ. This paper studied the pressure variation characteristics of ASJ machining system. Two models were built to describe the boosting and decompression processes of ASJ system. The decompression time of ASJ system can be predicted with the model of decompression process. The model of boosting process can be used to predict the target maximum pressure and the time consumption of boosting process, which are two important factors that have significant effects on the machining efficiency. The boosting process of the ASJ system is very important for machining. The influence of the compressibility of water and the friction resistance of the hydraulic system on the pressure variation characteristics of ASJ system during the machining process was also discussed.

A Study on Ultrasonic Torsional Vibration-Assisted Abrasive Waterjet Polishing of Ceramic Materials

Abrasive waterjet machining is considered as a promising technique in hard-brittle material polishing. In this paper, The ultrasonic torsional vibration is considered to apply on the workpiece to improve the abrasive waterjet polishing quality and efficiency. The process parameters in the ultrasonic torsional vibration-assisted abrasive waterjet polishing are optimized. The ultrasonic torsional vibration in the role of the abrasive waterjet polishing is investigated. The results show that the application of ultrasonic torsional vibration can effect of abrasive particle movement and increase the critical depth of the ceramic materials.

An experimental investigation on cutting performance of abrasive water jet machining of austenite steel (AISI 316L)

Abrasive water jet machining (AWJM) has proven to be an effective technology for processing variety of engineering materials. In this study, research work involved in experimental investigation on cutting performance of AWJM of austenite steel (AISI 316L) is described. AWJM process is characterised by a number of process parameters that affects the quality of machining. In the present work, influence of three parameters, namely pressure, traverse rate and stand-off distance on surface finish of austenite steel (AISI 316L) is investigated. Full factorial experimental design is applied for experimentation. Analysis of variance is performed and an empirical model is developed by multilinear regression analysis for surface roughness. After experimental analysis, conformation test is done. The results obtained in the present work are compared successfully with the published literature.

Vibration and Experimental Comparison of Machining Process

Abrasive water jet technology is among the unconventional ways of machining. In today's modern and progressive era is often used for cutting and machining of various types of materials because of lower costs and environmental impact, as the cutting tool is water, in our case, with the addition of abrasives. Objective of the measurements was to evaluate the impact of vibration on the technological head in abrasive water jet technology in changing the selected technological parameters and the flow rate of technological head. In the given experiment, the used material - steel Hardox 500 with a thickness of 10 mm. The effort was to investigate the effects of changes in the speed rate of technological head (by speeds - 40, 200, 400 mm / min) on the size of the vibration acceleration amplitude and its frequency. Based on the measured values ​​of vibration to the technological head create the database and from it is evaluated the data in selected softwares (LabVIEW, SignalExpress and Microsoft Excel). Findings and conclusions are formulated on the basis of graphical dependencies, envelopes frequency spectra and comparison chart of envelopes.